Raw water from fresh water sources such as wells, ponds, streams, lakes, etc. varies widely in quality and must generally be treated to make it potable. Often, it is necessary to treat water in remote areas for limited periods, such as during a military deployment, a remote short term construction project, after damage to a local permanent purification system, etc.
In addition, due to tanker truck spills, hazardous material leaks, etc. there are often needs for neutralizing and/or removing hazardous chemicals from the environment. In addition, where surface water is contaminated, decontamination and return to the surface is required without extensive treatment to the point where the water is potable.
A number of different water purification systems have been developed for treating water from a lake or river where the water is not highly contaminated . Generally, water is simply clarified, filtered to remove particulates and treated with chlorine.
Where both decontamination and disinfection of poor quality water is required, treatment with ozone is most effective. Ozone has been used for more than one hundred years to treat potable water supplies. Ozone is extensively used in municipal water plants in Europe, largely because of the poor quality of the water supplies. Ozone also provides superior disinfection and excels in the control of taste and color.
The extremely high effectiveness of ozone is due to its great oxidizing power. Ozone acts to oxidize pollutants and as a germicidal agent for microorganisms. Resistant sporulating types of bacteria are destroyed by ozone along with pathogenic and saprophytic organisms likely to be encountered in water. Ozone is used in the treatment of drinking water for bacterial disinfection, destruction of viruses and protozoans, increasing settleability characteristics, removal of algae, sulfides, cyanides, trihalomethane precursors organics, detergents, pesticides, phenols and humnic, fulvic and tannic acids. Soluble iron, manganese and other heavy metals are oxidized to insoluble forms that can be filtered from the water. Large, complex organic compounds are oxidized into smaller more easily biodegradable molecules. With the removal of organic compounds comes removal of odor, color and taste in the water. Ozone has been recognized to be significantly more effective than chlorine as a germicide against bacteria, viruses and protozoans.
Various devices and methods have been developed for purifying drinking water and waste water, such as those described by Laraus in U.S. Pat. No. 4,250,040 and Bhargava in 4,256,574. Prior ozone treatment plants have tended to be large, fixed plants for treating water at a particular location over a long period.
Mausegrover et al. describe a truck mounted ozone water treatment apparatus in U.S. Pat. No. 5,427,693. This apparatus includes a process tank for holding contaminated water and an ozone generator using a venturi to inject ozone into a water stream directed from the process tank to an infusion chamber. While probably effective for small quantities of lightly contaminated water, no provision is made for effectively filtering the water or of altering the throughput sequence for varying contamination. Also, the apparatus does not appear to be capable of routine transport by fixed wing aircraft or helicopters, limiting its effectiveness due to lack of mobility.
Thus, there is a continuing need for a portable ozone type water treatment system having improved decontamination capability, effective filtration for water of varying quality and that can adjust throughput rates and intensity Of treatment to accommodate widely different water quality characteristics.